This invention relates generally to fire extinguisher systems, and more particularly, to a fire extinguisher system which is deployed as a hood over a range top, and which can determine the presence of a fire continuously along a predetermined path so as not to be limited to discreet sensing zones.
For over three decades, various arrangements of range hood fire protection systems have been employed in commercial and residential environments. Generally, these known systems are characterized by the application of a tensile force on a cable which holds a fire extinguisher discharge valve in a closed position against a force applied by a resilient element, such as a spring, which would tend to open the discharge valve. In these known systems, the cable is segmented and provided with fusible links connecting the various segments to one another. Additionally, cable is trained within the hood along a plurality of cable supports, whereby the fusible links are advantageously disposed at strategic locations, such as directly over a burner of the range top.
In the event of a fire, the heat which builds up under the hood will melt the fusible link so as to release the tension on the segmented cable. Such release of the tension permits the valve to be urged into the open position, by operation of the resilient biasing element.
There are, of course, a variety of problems associated with conventional fusible link systems. One major problem is the great complexity and difficulty associated with installing one of these known systems. During installation, the cable segments must be cut to precise lengths, or otherwise the fusible links will not be located in the appropriate regions. This, of course, is essential to a proper installation since mislocation of one or more of the fusible links will result in a fire hazard. In addition, the apparatus must be configured so that there is a sufficient length of cable between each fusible link and its nearest cable support, so that, upon the release of the cable at the fusible link, there is a sufficient length of cable before every cable support such that the discharged valve can be release. In other words, placement of a fusible link too close to the cable support will cause S-hooks or cable ties to bind at the cable support before the discharge valve has been moved sufficiently to enter a fully open state. Clearly, fusible link systems require great skill in their installation.
A still further problem which is associated with the installation of fusible link fire extinguisher systems is that, particularly in installations where the chemical tank is located remotely, possibly in another room, the cable must be trained along and through walls, and steps must be taken to ensure that the cable does not bind anywhere therealong. Of course, throughout its traverse, the cable must provide the tensile force which is required to prevent the biasing member from urging the discharge valve into the open position. Of course, if the cable binds anywhere along its path, the discharge valve can be retained in the closed position, notwithstanding that one or more of the fusible elements has melted. The results, of course, could be disastrous.
Another problem with fusible link systems is that they are not readily adaptable to changes in the configuration of the burners of the range top, without undergoing essentially a complete cable reinstallation process. More specifically, if it is desired to change the specific location of the region desired to be protected from a fire hazard under the protective hood, it is necessary in conventional fusible link systems that the entire fusible link and cable system be removed and resized so that the fusible links can be relocated. Of course, if it is necessary to protect an area which was not traversed over by the cable, significant modifications, such as the inclusion of new cable supports, will be required. Such cable supports must be structurally quite sound as they are generally required to bear the tensile force in the cable.
It is, therefore, an object of this invention to provide a simple and reliable residential range hood fire extinguisher system which can easily be installed without requiring extensive experience or expertise.
It is another object of this invention to provide a range hood fire extinguisher system which affords heat responsive sensing over a continuous predetermined region.
It is also an object of this invention to provide a fire extinguisher system which continuously monitors itself for the development of fault conditions which would render the system inoperative.
It is a further object of this invention to provide a fire extinguisher system which can easily trigger discharge of an extinguisher material from a remote location without the need to extend lengthy cables under tension.
It is additionally an object of this invention to provide a range hood fire protection system which can easily be reconfigured, as desired.
It is a yet further object of this invention to provide a fire extinguisher system which provides a visual indication of the existence of a fault condition.
It is also another object of this invention to provide a range hood fire extinguisher system which does not require the complicated mechanical support arrangements provided for segment cable and fusible link systems.
It is yet an additional object of this invention to provide a range hood fire extinguisher system which is actuatable with only a small amount of electrical current, whereby protection is achieved without requiring the electrical mains to be operable at all times.
It is still another object of this invention to provide a range hood fire extinguisher system which is easy to maintain and test for proper operation, and does not have associated with it the hazards of a tensioned cable.
It is a yet further object of this invention to provide a range hood fire extinguisher system which is easily adapted for different fire hazard temperatures.
It is also a further object of this invention to provide a simple and inexpensive range hood fire extinguisher system which does not require the strong cable supports of known arrangements.